Reflection Driven Ship Wake Contrasts in the Infrared

Abstract

Contrast between a ship's wake and a rough sea is considered from a probabilistic approach. A probability slope model of a rough sea is given in terms of the fraction of facets that reflect and emit infrared radiation into a sensor. It is shown computationally that the rough sea, when viewed near grazing, can appear much cooler than a smooth sea. Furthermore, the expected contrast between a ship's wake and its background can be driven by a reflection phenomenon rather than by a real temperature difference. Also, it is shown that the apparent temperature of a wake can be warmer than its background even though the intrinsic temperatures of the wake and background are the same. The rough sea background model takes into account self-shadowing of the sea surface that is important when the sea is viewed at newer grazing angles. Keywords: Ocean surface roughness; Infrared tracking; Infrared contrast.

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Document Details

Document Type
Technical Report
Publication Date
Aug 23, 1988
Accession Number
ADA198991

Entities

People

  • I. B. Schwartz
  • R. G. Priest

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Ground and Sea Platforms
  • Sensors

DTIC Thesaurus Topics

  • Air Force
  • Classification
  • Coordinate Systems
  • Detection
  • Equations
  • Geometry
  • Grazing Angles
  • Infrared Radiation
  • Probability
  • Probability Density Functions
  • Radiation
  • Random Variables
  • Reflection
  • Reflectivity
  • Security
  • Statistics
  • Surface Roughness

Readers

  • Computational Modeling and Simulation
  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers
  • Spectroscopy.